diff --git a/planning/src/file_io/pln_blif_file.cpp b/planning/src/file_io/pln_blif_file.cpp
index 51976959..40525f4f 100644
--- a/planning/src/file_io/pln_blif_file.cpp
+++ b/planning/src/file_io/pln_blif_file.cpp
@@ -1199,12 +1199,6 @@ bool BLIF_file::createNodes() noexcept {
       if (not starts_w_subckt(cs + 1, len - 1))
         continue;
       Fio::split_spa(lines_[L], V);
-      //if (L == 48) {
-      //  string delWire1151 = "$delete_wire$1151";
-      //  lputs8();
-      //  int dTerm = findTermByNet(V, delWire1151);
-      //  lprintf("  dTerm= %i\n", dTerm);
-      //}
       if (V.size() > 1 and V.front() == ".subckt") {
         Prim_t pt = pr_str2enum( V[1].c_str() );
         if (pr_is_MOG(pt)) {
@@ -1997,7 +1991,35 @@ bool BLIF_file::checkClockSepar(vector<BNode*>& clocked) noexcept {
     }
   }
 
-  if (trace_ >= 6) {
+  // -- paint top-output nodes (and their incoming wires) Black
+  for (BNode* p : topOutputs_) {
+    const BNode& port = *p;
+    assert(!port.out_.empty());
+    assert(port.nw_id_);
+    if (!port.nw_id_)
+      continue;
+    NW::Node& nd = pg_.nodeRefCk(port.nw_id_);
+    nd.paintBlack();
+    uint par = port.parent_;
+    while (par) {
+      const BNode& parBn = bnodeRef(par);
+      assert(parBn.nw_id_);
+      if (!parBn.nw_id_)
+        break;
+      if (!parBn.is_WIRE())
+        break;
+      NW::Node& nwn = pg_.nodeRefCk(parBn.nw_id_);
+      nwn.paintBlack();
+      if (nwn.parent()) {
+        NW::Node& nwp = pg_.nodeRefCk(nwn.parent());
+        if (map_pg2blif(nwp.id_) == parBn.id_)
+          nwp.paintBlack();
+      }
+      par = parBn.parent_;
+    }
+  }
+
+  if (trace_ >= 5) {
     lputs("   (Pin Graph)  *** summary after B ***");
     pg_.printSum(ls, 0);
     lputs();
@@ -2025,13 +2047,16 @@ bool BLIF_file::checkClockSepar(vector<BNode*>& clocked) noexcept {
   bool color_ok = true;
   CStr viol_prefix = "  [Error] clock-data separation ERROR";
 
-  // -- check that end-points of red edges are red
+  // -- check that end-points of red edges are red,
+  //    the destination node may be black (output port)
   for (NW::cEI E(pg_); E.valid(); ++E) {
     const NW::Edge& ed = *E;
     if (not ed.isRed())
       continue;
     NW::Node& p1 = pg_.nodeRef(ed.n1_);
     NW::Node& p2 = pg_.nodeRef(ed.n2_);
+    if (p2.isBlack())
+      continue;
     if (!p1.isRed() or !p2.isRed()) {
       color_ok = false;
       p1.markViol(true);
@@ -2170,50 +2195,57 @@ bool BLIF_file::createPinGraph() noexcept {
 
   // -- link in-ports to out-ports via feedthrough wires
   for (BNode* x : fabricRealNodes_) {
-    if (x->is_WIRE()) {
-      BNode& w = *x;
-      assert(w.data_.size() == 2);
-      const string& w_inp = w.data_.front();
-      const string& w_out = w.data_.back();
-      BNode* iport = findInputPort(w_inp);
-      if (!iport)
-        continue;
-      BNode* oport = findOutputPort(w_out);
-      if (!oport)
-        continue;
-      assert(iport->isTopInput());
-      assert(oport->isTopOutput());
-      // NW-nodes for i/o ports should exist already
-      assert(iport->nw_id_);
-      assert(oport->nw_id_);
-      assert(pg_.hasNode(iport->nw_id_));
-      assert(pg_.hasNode(oport->nw_id_));
-      assert(map_pg2blif(iport->nw_id_) == iport->id_);
-      assert(map_pg2blif(oport->nw_id_) == oport->id_);
-
-      // NW keys and nodes for wire pseudo-cell:
-      uint64_t w_k1 = hashCantor(w.id_, 1) + max_key1;
-      uint64_t w_k2 = hashCantor(w.id_, 2) + max_key1;
-      assert(w_k1);
-      assert(w_k2);
-      assert(w_k1 != w_k2);
-      uint w_n1 = pg_.insK(w_k1);
-      assert(w_n1);
-      uint w_n2 = pg_.insK(w_k2);
-      assert(w_n2);
-      pg2blif_.emplace(w_n1, w.id_);
-      pg2blif_.emplace(w_n2, w.id_);
-      pg_.setNodeName4(w_n1, w.id_, w.lnum_, 1, "FTwireI");
-      pg_.setNodeName4(w_n2, w.id_, w.lnum_, 2, "FTwireO");
-
-      // link feedthrough:
-      uint ee;
-      ee = pg_.linkNodes(iport->nw_id_, w_n1, false);
-      ee = pg_.linkNodes(w_n1, w_n2, true);
-      ee = pg_.linkNodes(w_n2, oport->nw_id_, false);
-      if (trace_ >= 11)
-        lprintf("\t\t ee = %u\n", ee);
-    }
+    BNode& w = *x;
+    if (not w.is_WIRE())
+      continue;
+    assert(w.data_.size() == 2);
+    const string& w_inp = w.data_.front();
+    const string& w_out = w.data_.back();
+    BNode* iport = findInputPort(w_inp);
+    if (!iport)
+      continue;
+    BNode* oport = findOutputPort(w_out);
+    if (!oport)
+      continue;
+    assert(iport->isTopInput());
+    assert(oport->isTopOutput());
+    // NW-nodes for i/o ports should exist already
+    assert(iport->nw_id_);
+    assert(oport->nw_id_);
+    assert(pg_.hasNode(iport->nw_id_));
+    assert(pg_.hasNode(oport->nw_id_));
+    assert(map_pg2blif(iport->nw_id_) == iport->id_);
+    assert(map_pg2blif(oport->nw_id_) == oport->id_);
+
+    // NW keys and nodes for wire pseudo-cell:
+    uint64_t w_k1 = hashCantor(w.id_, 1) + max_key1;
+    uint64_t w_k2 = hashCantor(w.id_, 2) + max_key1;
+    assert(w_k1);
+    assert(w_k2);
+    assert(w_k1 != w_k2);
+    uint w_n1 = pg_.insK(w_k1);
+    assert(w_n1);
+    uint w_n2 = pg_.insK(w_k2);
+    assert(w_n2);
+    pg2blif_.emplace(w_n1, w.id_);
+    pg2blif_.emplace(w_n2, w.id_);
+    w.nw_id_ = w_n2;
+    pg_.nodeRef(w_n1).markWire(true);
+    pg_.nodeRef(w_n2).markWire(true);
+    pg_.setNodeName4(w_n1, w.id_, w.lnum_, 1, "FTwireI");
+    pg_.setNodeName4(w_n2, w.id_, w.lnum_, 2, "FTwireO");
+
+    // make sure BNode::parent_ links are set
+    oport->parent_ = w.id_;
+    w.parent_ = iport->id_;
+
+    // link feedthrough:
+    uint ee;
+    ee = pg_.linkNodes(iport->nw_id_, w_n1, false);
+    ee = pg_.linkNodes(w_n1, w_n2, true);
+    ee = pg_.linkNodes(w_n2, oport->nw_id_, false);
+    if (trace_ >= 11)
+      lprintf("\t\t ee = %u\n", ee);
   }
 
   // -- link from input ports to fabric
diff --git a/planning/src/main.cpp b/planning/src/main.cpp
index 827508cf..ad4dc2f0 100644
--- a/planning/src/main.cpp
+++ b/planning/src/main.cpp
@@ -1,4 +1,4 @@
-static const char* _pln_VERSION_STR = "pln0366";
+static const char* _pln_VERSION_STR = "pln0367";
 
 #include "RS/rsEnv.h"
 #include "RS/rsDeal.h"
diff --git a/planning/src/util/nw/Nw.cpp b/planning/src/util/nw/Nw.cpp
index 44c8549f..2e296b8e 100644
--- a/planning/src/util/nw/Nw.cpp
+++ b/planning/src/util/nw/Nw.cpp
@@ -318,6 +318,26 @@ uint NW::countRedNodes() const noexcept {
   return cnt;
 }
 
+uint NW::countBlackNodes() const noexcept {
+  uint cnt = 0;
+  if (empty()) return 0;
+  for (cNI I(*this); I.valid(); ++I) {
+    if (I->isBlack())
+      cnt++;
+  }
+  return cnt;
+}
+
+uint NW::countWireNodes() const noexcept {
+  uint cnt = 0;
+  if (empty()) return 0;
+  for (cNI I(*this); I.valid(); ++I) {
+    if (I->wire_flag_)
+      cnt++;
+  }
+  return cnt;
+}
+
 bool NW::hasClockNodes() const noexcept {
   if (empty()) return false;
   for (cNI I(*this); I.valid(); ++I) {
diff --git a/planning/src/util/nw/Nw.h b/planning/src/util/nw/Nw.h
index d98ea570..82c75cfd 100644
--- a/planning/src/util/nw/Nw.h
+++ b/planning/src/util/nw/Nw.h
@@ -44,7 +44,8 @@ struct NW {
   static constexpr uint c_darkorchid4 = 13;
   static constexpr uint c_cyan = 14;
   static constexpr uint c_goldenrod3 = 15;
-  static constexpr uint c_MAX_COLOR = 15;
+  static constexpr uint c_Black = 16;
+  static constexpr uint c_MAX_COLOR = 16;
 
   struct Edge {
     uint id_ = 0;
@@ -64,6 +65,8 @@ struct NW {
     void paint(uint col) noexcept { color_ = col; }
     void paintRed() noexcept { color_ = c_Red; }
     bool isRed() const noexcept { return color_ == c_Red; }
+    void paintBlack() noexcept { color_ = c_Black; }
+    bool isBlack() const noexcept { return color_ == c_Black; }
 
     bool valid() const noexcept { return n1_; }
     void inval() noexcept { ::memset(this, 0, sizeof(*this)); }
@@ -156,6 +159,7 @@ struct NW {
     void markOut(bool val) noexcept { out_flag_ = val; }
     void markClk(bool val) noexcept { clk_flag_ = val; }
     void markViol(bool val) noexcept { viol_flag_ = val; }
+    void markWire(bool val) noexcept { wire_flag_ = val; }
     void markPrim(uint16_t pt) noexcept { prim_ = pt; }
 
     bool isClk() const noexcept { return clk_flag_; }
@@ -170,6 +174,8 @@ struct NW {
     void paint(uint col) noexcept { color_ = col; }
     void paintRed() noexcept { color_ = c_Red; }
     bool isRed() const noexcept { return color_ == c_Red; }
+    void paintBlack() noexcept { color_ = c_Black; }
+    bool isBlack() const noexcept { return color_ == c_Black; }
 
     // DATA:
     vecu edges_;
@@ -192,6 +198,7 @@ struct NW {
     bool out_flag_ = false;
     bool clk_flag_ = false;
     bool viol_flag_ = false;
+    bool wire_flag_ = false;
     string name_;
   };
 
@@ -280,6 +287,8 @@ struct NW {
   bool hasClockNodes() const noexcept;
   uint countClockNodes() const noexcept;
   uint countRedNodes() const noexcept;
+  uint countBlackNodes() const noexcept;
+  uint countWireNodes() const noexcept;
   uint countNamedNodes() const noexcept;
 
   void getNodes(vecu& V) const noexcept { V = nids_; }
diff --git a/planning/src/util/nw/Nw_io.cpp b/planning/src/util/nw/Nw_io.cpp
index 43427a0f..948d6a79 100644
--- a/planning/src/util/nw/Nw_io.cpp
+++ b/planning/src/util/nw/Nw_io.cpp
@@ -523,10 +523,13 @@ uint NW::printSum(ostream& os, uint16_t forDot) const noexcept {
   uint numNamedNodes = countNamedNodes();
   uint numRedNodes = countRedNodes();
   uint numRedEdges = countRedEdges();
+  uint numBlackNodes = countBlackNodes();
+  uint numWireNodes = countWireNodes();
 
   dot_comment(os, forDot);
-  os_printf(os, "#NamedNodes=%u  #RedNodes= %u  #RedEdges= %u\n",
-            numNamedNodes, numRedNodes, numRedEdges);
+  os_printf(os,
+        "#NamedNodes=%u  #RedN= %u  #RedE= %u  #BlackN= %u  #WireN= %u\n",
+        numNamedNodes, numRedNodes, numRedEdges, numBlackNodes, numWireNodes);
 
   dot_comment(os, forDot);
   os_printf(os, "nr=(%u,%u) #Inp=%u #Out=%u\n",